Methods, systems, and computer program products that request updated host screen information from host systems in response to notification by servers

ABSTRACT

A method of providing updated host screen information to a client application utilizing a request-response communications model includes establishing a first connection between the client application and a server application, wherein the server application provides updated host screen information to the client application in response to requests from the client application. A second connection is established between a monitor application and the server application. A notification of the availability of updated host screen information is received via the second connection at the monitor application. The updated host screen information is requested over the first connection responsive to receiving the notification. The requested updated host screen information is received at the client application and displaying utilizing the client application. Related systems and computer program products are also disclosed.

FIELD OF THE INVENTION

The present invention relates to network computing in general, and moreparticularly, to the communication between servers and clients.

BACKGROUND OF THE INVENTION

Some applications that run on legacy host systems can be accessed usinga display terminal running a terminal protocol. The terminal protocolmay enable communications to and from the display terminal, such as whena screen is transmitted to the display terminal and when user input istransmitted to the host system. Such protocols are sometimes referred toas “2 way asynchronous” communications. In such a terminal protocol, forexample, updated (or new) screens generated by the host application maybe transmitted to the display terminal without a request from the user.In other words, updated screens may be automatically transmitted to thedisplay terminal.

It is also known to provide access to applications running on legacyhost systems over a network, using a server running a terminal emulationprogram. For example, screens generated by host applicationstraditionally accessed using a display terminal using a terminalprotocol may be reformatted by a server terminal emulation program intomarkup language. The markup language format may then be provided inresponse to a request from a web browser application. Thus, the use of aserver terminal emulation program enables the legacy host system to beaccessed using a browser over, for example, the World Wide Web (WWW),the internet or an intranet, rather than a display terminal over aterminal protocol.

Unfortunately, some of the communications protocols used to provideterminal emulation between browsers and legacy host systems may notprovide the same communications functions provided by the terminalprotocols described above. For example, the Hypertext Transport Protocol(HTTP) utilizes a synchronous “request-response communications model.”In HTTP, the server typically only provided information to the browserin response to a request from the browser. In such a system, it may bedifficult to provide the asynchronous communications described above. Inparticular, it may be difficult to provide updated screens to thebrowser automatically.

Some systems may allow a user to provide manual requests for updatedscreens to the legacy host system which may cause the server to providean updated screen generated by the legacy host system. For example, arefresh button may be provided wherein the user may request an updatedscreen from the legacy host system. In addition to requiring userintervention, this type of solution to the synchronous communicationsproblem may not provide an updated host screen because the refreshrequest may occur prior to the generation of an updated screen.Accordingly, there is a need for methods, systems, and computer programproducts that allow improved communication with legacy host applicationsover the WWW.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to allow improvedcommunication between client applications and legacy host applicationswhere a synchronous communication model is used.

It is a further object of the present invention to allow synchronousclients to receive asynchronous communications without requiring userintervention.

These and other objects of the present invention are provided bymethods, systems, and computer program products that establish a firstconnection between a client application and a server application,wherein the server application provides updated host screen informationto the client application in response to requests from the clientapplication by establishing a second connection between a monitorapplication and the server application. A notification of theavailability of updated host screen information is then received via thesecond connection at the monitor application and a request for updatedhost screen information is transmitted over the first connectionresponsive to receiving the notification. The requested updated hostscreen information is received at the client application and displayedutilizing the client application.

By utilizing an alternate or second connection to the client, the servermay notify the client of the availability of host screen informationand, thereby, prompt the client to request the host screen informationusing the first, synchronous, connection. Because client applicationrequests the updated host screen information in response to thenotification from the server, the need for the user to manually requestupdated host screen information may be reduced.

In one embodiment, the monitoring application which monitors thealternate connection for notifications may be relatively smallnotification code or an applet that is embedded in a web pagedescription (HTML) provided to the client. When executed, thenotification code establishes a notification connection to the server.When the notification code receives notification of the availability ofupdated host screen information, the notification code signals theclient application and terminates. Accordingly, the relatively smallnotification code can be more readily embedded in the HTML descriptionand may reduce the time needed to download the updated host screeninformation.

As will be appreciated by those of skill in the art, the presentinvention may be embodied as methods, systems (apparatus) and/orcomputer program products.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of first embodiment of a system according tothe present invention.

FIG. 2 is a block diagram of a second embodiment of a system accordingto the present invention.

FIG. 3 is a block diagram of a third embodiment of a system according tothe present invention.

FIG. 4 is a flowchart that illustrates operations of a system accordingto the present invention.

FIG. 5 is a flowchart that illustrates operations of a system includingdownloading of notification code according to the present invention.

FIG. 6 is a capture of a host screen generated by a host systemincluding host screen information.

FIG. 7 is a capture of a screen rendered by a client application screenincluding formatted updated host screen information.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now will be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Likenumbers refer to like elements throughout.

As will be appreciated by one of skill in the art, the present inventionmay be embodied as methods, systems or computer program products.Accordingly, the present invention may take the form of an entirelyhardware embodiment, an entirely software embodiment or an embodimentcombining software and hardware aspects.

The present invention is described herein using flowchart illustrationsand block diagrams. It will be understood that each block of the blockdiagrams or flowchart illustrations, and combinations of blocks in theblock diagrams or flowchart illustrations, can be implemented bycomputer program instructions. These program instructions may beprovided to a processor(s) within a computer system, such that theinstructions which execute on the processor(s) create means forimplementing the functions specified in the block diagrams or flowchartblock or blocks. The computer program instructions may be executed bythe processor(s) to cause a series of operational steps to be performedby the processor(s) to produce a computer implemented process such thatthe instructions which execute on the processor(s) provide steps forimplementing the functions specified in the block diagrams or flowchartblock or blocks.

Accordingly, blocks of the block diagrams or flowchart illustrationssupport combinations of means for performing the specified functions,combinations of steps for performing the specified functions and programinstruction means for performing the specified functions. It will alsobe understood that each block of the block diagrams or flowchartillustrations, and combinations of blocks in the flowchartillustrations, can be implemented by special purpose hardware-basedsystems which perform the specified functions or steps, or combinationsof special purpose hardware and computer instructions.

The clients and the servers described herein (in whole or in part) maybe remote from one another or resident in the same location. The phrase“client application” includes applications, such as browsers, thatrequest information, such as host screens generated by host systems. Asused herein the term “terminal emulation” includes any form of user orprogrammable access and interactions with host screens generated by hostsystems. Although the present invention is described with reference toterminal emulation, it will be understood that the scope of the presentinvention includes other systems and services.

FIG. 1 is a block diagram of a first embodiment of a system according tothe present invention. According to FIG. 1, a server 110 providesterminal emulation sessions for a client application 115 to a hostsystem 105 that runs legacy host applications. The host system 105generates output in the form of host datastreams 120 that include hostscreen information such as tables, paragraphs of data and the like whichcan appear as part of a host screen 121. The host datastreams 120,including host screen information, are transmitted to the server 110.

During operation, the server 110 receives host screen information fromthe host system 105. The host screen information can be generatedresponsive to a request by the server 110 or responsive to non-serverevents. For example, the host system 105 can transmit host screeninformation to the server 110 in response to user input or a change inthe status of the host system 105. Accordingly, the host screeninformation generated by the host system 105 can update the host screeninformation previously received by the server 110. It will be understoodthat the phrase “updated host screen information” includes host screeninformation not previously received by the server 110 as well as hostscreen information previously received by the server 110. For example,when the server 110 receives host screen information previously receivedby the server 110, the host screen information provided by the hostsystem 105 represents updated host screen information.

When the server 110 receives updated host screen information, anApplication Programming Interface (API) 135 generates a message which isused to notify the client application 115 that the server 110 hasreceived updated host screen information. The notification istransmitted to the client application 115 over a notification connection122 from a first server socket 117 to a first client socket 119. The APIcan be Extended High Level Language API, Host Access Class Library, OpenHost Interface Objects, or the like.

The server 110 receives requests for updated screen information from theclient application 115 via a request connection 124. It will beunderstood to those having skill in the art that the request connection124 may be, for example, the HTTP connection and can carry informationaccording to the response-request communication model. It will beunderstood that, the server can be a mid-tier WWW server that conductsterminal emulation sessions for multiple client applications 115 runningon respective client workstations.

A connection can be provided by a communications protocol, such asTransmission Control Protocol/Internet Protocol (TCP/IP). A connectionbetween applications can be accessed using sockets. For example,according to FIG. 1, the API 135 accesses the first connection 122 tothe client application 115 via the first server socket 117. The clientapplication 115 accesses the first connection 122 via the first clientsocket 119. The notification connection 122 and the request connection124 can be provided over separate communications links or a singlecommunications link, such as a modem.

An application 130 running on the server 110 formats the updated hostscreen information as web page descriptions using Host On Demand (HOD)functions to generate a markup language format, such as ExtensibleMarkup Language (XML) or Hypertext Markup Language (HTML) for theupdated host screen information. The formatted updated host screeninformation (e g, a web page description) is transmitted to the clientapplication 115 over the request connection 124 from a second serversocket 127 to a second client socket 125. HOD functions and reformattingof updated host screen information are discussed, for example, in U.S.patent application Ser. No. 09/353,218 filed Jul. 14, 1999, entitledMethods, Systems, and Computer Program Products For Applying Styles toHost Screens Based on Host Screen Content which is assigned to theassignee of the present application and which is incorporated herein byreference in its entirety.

The client application 115 displays the formatted updated host screeninformation as a web page 145. The formatted updated host informationcan include notification code 140 or application, such as a Java®applet, which can be invoked by the client application 115. For example,the server 110 can embed the notification code 140 in the formattedupdated host information. When the formatted updated host information isreceived, the client application 115 recognizes the embeddednotification code 140 and runs it. Alternately, the formatted updatedhost screen information includes a reference locator, such as a UniformResource Locator (URL) which can be used to locate and download thereferenced notification code 140. The client application 115 can be aweb browser, such as Netscape Navigator® marketed by NetscapeCommunications Corporation based in Mountain View, Calif.

The client application 115 can run on a client workstation which is notshown.

The client workstation can be an input device with a display such as acomputer terminal running the client application 115, a personalcomputer, a networked computer, a smart phone, a personal digitalassistant, a handheld computer, or the like.

In operation, the notification code 140 establishes the notificationconnection by initializing the first client socket 119 to the firstconnection 122 and waits for a notification from the server 110 over thenotification connection 122. The notification from the server 110indicates that the server 110 has received updated host screeninformation associated with a terminal emulation session conducted forthe client application 115. The notification code 140 transmits arequest for formatted updated host screen information to the server 110over the request connection 124. According to the present invention, therequest for the updated host screen information via the requestconnection 124 is responsive to the notification from the server via thenotification connection 122.

FIG. 2 is a block diagram of a second embodiment of a system accordingto the present invention wherein the server 110 provides terminalemulation session applications 130 a-c for a plurality of respectiveclient applications 115 a-c. Each application 130 a-c identifies therequests received from the respective client application 115 a-c. Inparticular, Identifiers (IDs) are associated with requests made by eachclient 115 a-c. For example, the ID included in a first request from thefirst client application 115 a for updated host screen informationidentifies the first client application 115 a, a second request from thesecond client application 115 b for updated host screen informationidentifies the second client application 115 b, and a third request fromthe third client application 115 c for updated host screen informationidentifies the third client application 115 c. Accordingly, therespective application 130 a-c can transmit the formatted updated hostscreen information to the appropriate client application 115 a-c.

FIG. 3 is a block diagram of a third embodiment of a system according tothe present invention. According to FIG. 3, paging messages are issuedto the host system 105. The paging messages can include page informationsuch as telephone numbers, text information, audio information, displayinformation, or the like. The page information is transmitted to theserver 110 which notifies the notification code 140 via the requestconnection 122. The client application 115 requests the page informationfrom the server 110 over the request connection 124 in response to thenotification. The server 110 transmits the page information to theclient application 115 which can provide the page information to theuser.

FIG. 4 is a flowchart that illustrates operations of a system accordingto the present invention. According to FIG. 4, the request connection124 is established between the client application 115 and the server 110(block 405). The server 110 provides formatted updated host screeninformation to the client application 115 over the request connection124 in response to requests from the client application 115. Thenotification connection 122 is established between the notification code140 and the server 110 (block 410). The notification code 140 monitorscommunications from the server 110 over the notification connection 122.

The server 110 receives updated host screen information from the hostsystem 105 and notifies the client application 115 of the availabilityof the updated host screen information via the notification connection122 (block 415). For example, the server 110 can transmit a message viathe notification connection 122 to the notification code 140. Uponreceiving the notification of available updated host screen information,the client application 115 transmits a request for the formatted updatedhost screen information to the server 110 (block 420) via the requestconnection 124. The server 110 responds to the request by transmittingthe formatted updated host screen information to the client application115 via the request connection 124. The formatted updated host screeninformation is received by the client application 115 (block 425) anddisplayed (block 430).

FIG. 5 is a flowchart that illustrates operations of a system includingdownloading of notification codes according to the present invention.According to FIG. 5, the server 110 initializes the first server socket117 of the notification connection 122 (block 505). Formatted updatedhost screen information (web page) is downloaded from the server 110 tothe client application 115 over the request connection 124 (block 510).The formatted updated host screen information includes a notificationcode 140 which can be run by the client application 115.

The notification code 140 initializes the first client socket 119,establishing the notification connection 122 between the server 110 andthe notification code 140 and blocks on a read of the first clientsocket 119 (block 515). In other words, the notification code 140continues to wait for a message to be received from the server 110 overthe notification connection 122.

When the server 110 receives updated host screen information from thehost system 105 (block 525), the server 110 transmits a notificationmessage to the notification code 140 over the notification connection(block 530). The notification code 140 receives the notification messageand signals the client application 115. The notification code 140 maythen terminate.

The client application 115 requests formatted updated host screeninformation from the server 110 (block 535) in response to thenotification message, whereupon the server 110 transmits the formattedupdated host screen information received from the host system 105 (block540). The formatted updated host screen information includes anothernotification code 140 which initializes the first client socket 119 ofthe notification connection 122 between the server 110 and the clientapplication (block 515).

A detailed example of operations of the present invention will now bedescribed in reference to FIGS. 6 and 7. After establishing the requestand notification connections 122, 124 the host screen 121, includinghost screen information, shown in FIG. 6 is generated by the host system105. The server 110 notifies the notification code 140 of theavailability of updated hosts screen information over the notificationconnection 122.

The notification code 140 receives the notification and signals theclient application 115. The client application 115 requests theformatted updated host screen information over the request connection124. The server 110 formats the host screen information as fields asdescribed in Methods, Systems, and Computer Program Products forApplying Styles to Host Screens Based on Host Screen Content. Forexample, the first row of the name information can be formatted as:

-   -   Field 1: position=“1042” length=“26” protected=“true”        numeric=“true” hidden=“false” reset=“false” modified=“false”        text=“Li, Michael C T”    -   Field 2: position=“1069” length=“1” protected=“false”        numeric=“false” hidden=“false” reset=“false” modified=“false”        underscore=“true” color=“cyan” text=“ ”    -   Field 3: position=“1072” length=“5” protected=“false”        numeric=“false” hidden=“false” reset=“false” modified=“false”        text=“Reg”    -   Field 4: position=“1078” length=“8” protected=“false”        numeric=“false” hidden=“false” reset=“false” modified=“false”        color=“cyan” text=“4095”    -   Field 5: position=“1087” length=“33” protected=“false”        numeric=“false” hidden=“false” reset=“false” modified=“false”        text=“IBMUSM3”

The fields included in the updated host screen information aretranslated to HTML, as shown below, to provide the formatted updatedhosts screen information. It will be understood that fields included inthe updated hosts screen information that are not recognized by theapplication 130 can be ignored.

-   -   <TR>    -   <TD>    -   Li, Michael    -   C.T.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp        ;&nbsp;&nbsp;    -   </TD>    -   <TD>    -   <input type=“text” value=“ ” length=“1” maxlength=“1”>    -   </TD>    -   <TD>    -   Reg    -   </TD>    -   <TD>    -   <FONT COLOR=“#00FFFF”>4095</FONT>    -   </TD>    -   <TD>    -   IBMUSM    -   </TD>    -   </TR>

The notification code 140, or a reference thereto, is included in theHTML description. For example, a reference to the notification code 140can be expressed as:

-   -   <HTML>        -   . . .        -   HTML description of updated host screen information        -   . . .        -   <Applet Code=“MyClass.class”>    -   <HTML>

The HTML description of the updated host screen information isdownloaded to the client application 115. The client applicationexamines the HTML description, recognizes the reference to thenotification code “MyClass.class”, accesses the notification code 140,runs the notification code 140, and renders the formatted updated hostscreen information as shown in FIG. 7. The notification code 140initializes the first client socket 119 and waits for a new notificationof available updated host screen information over the notificationconnection 122.

In the drawings and specification, there have been disclosed typicalpreferred embodiments of the invention and, although specific terms areemployed, they are used in a generic and descriptive sense only and notfor purposes of limitation, the scope of the invention being set forthin the following claims.

1. A method of providing updated legacy host screen information to aclient application as terminal emulation between a legacy host systemand the client application the client application utilizing arequest-response communications model, the method comprising:establishing a first connection between the client application and aserver application, wherein the server application provides updatedlegacy host screen information to the client application in response torequests from the client application using an HTTP request-responsecommunications model, wherein the updated legacy host screen informationis based on asynchronously generated information formatted for acharacter terminal of a host legacy system as part of terminal emulationprovided between the client application and the host legacy system;establishing a second connection between a monitor application and theserver application; receiving a notification of the availability ofupdated legacy host screen information via the second connection at themonitor application using the HTTP request-response communicationsmodel; requesting the updated legacy host screen information over thefirst connection using HTTP request-response communications modelresponsive to receiving the notification; receiving the requestedupdated legacy host screen information at the client application; anddisplaying the received updated host screen information utilizing theclient application.
 2. The method of claim 1, wherein the clientapplication comprises a web browser and wherein the monitoringapplication comprises notification code.
 3. The method of claim 2,wherein the notification code is provided with updated legacy hostscreen information, the method further comprising the steps of:extracting the notification code from the host screen information; andexecuting the notification code.
 4. The method of claim 2, wherein theupdated legacy host screen information comprises a Markup Language. 5.The method of claim 1, wherein the updated legacy host screeninformation comprises terminal emulation information.
 6. The method ofclaim 1, wherein the first and second connections are conducted via asingle communications link.
 7. The method of claim 1, wherein the serverapplication provides updated legacy host screen information to a secondclient application in response to requests from the second clientapplication, the method further comprising: identifying the clientapplication that requested the updated legacy host screen information.8. A system of providing updated legacy host screen information to aclient application as terminal emulation between a legacy host systemand the client application, the client application utilizing arequest-response communications model, the system comprising: means forestablishing a first connection between the client application and aserver application, wherein the server application provides updatedlegacy host screen information to the client application in response torequests from the client application using an HTTP request-responsecommunications model, wherein the updated legacy host screen informationis based on asynchronously generated information formatted for acharacter terminal of a legacy host system as part of terminal emulationprovided between the client application and the host legacy system;means for establishing a second connection between a monitoringapplication and the server application; means for receiving updatedlegacy host screen information from the legacy host system; means fortransmitting a notification of the availability of updated legacy hostscreen information to the monitoring application over the secondconnection using the HTTP request-response communications modelresponsive to receiving the updated legacy host screen information;means for receiving a request for the updated legacy host screeninformation from the client application over the first connection usingthe HTTP request-response communications model; and means fortransmitting the received updated legacy host screen information to theclient application over the first connection in response to receivingthe request for the updated legacy host screen information from theclient application.
 9. The system of claim 8, wherein the clientapplication comprises a web browser and wherein the monitoringapplication comprises an, notification code.
 10. The system of claim 9,wherein the means for transmitting the received updated legacy hostscreen information further comprises means for incorporating thenotification code in the updated legacy host screen informationtransmitted to the client application.
 11. The system of claim 8,wherein the server application provides updated legacy host screeninformation to a second client application in response to requests fromthe second client application, the system comprising: means foridentifying the client application that requested the updated legacyhost screen information.
 12. A computer program product that providesupdated legacy host screen information to a client application asterminal emulation between a legacy host system and the clientapplication, the client application utilizing a request-responsecommunications model, the computer program product comprising: acomputer-readable storage medium having computer-readable program codemeans embodied in said medium, said computer-readable program code meanscomprising: computer readable program code means for establishing afirst connection between the client application and a serverapplication, wherein the server application provides updated legacy hostscreen information to the client application in response to requestsfrom the client application using an HTTP request-responsecommunications model, wherein the updated legacy host screen informationis based on asynchronously generated information formatted for acharacter terminal of a legacy host system as part of terminal emulationprovided between the client application and the host legacy system;computer readable program code means for establishing a secondconnection between a monitor application and the server application;computer readable program code means for receiving a notification of theavailability of updated legacy host screen information via the secondconnection at the monitor application using the HTTP request-responsecommunications model; computer readable program code means forrequesting the updated legacy host screen information over the firstconnection using the HTTP request-response communications modelresponsive to receiving the notification; computer readable program codemeans for receiving the requested updated legacy host screen informationat the client application; and computer readable program code means fordisplaying the received updated legacy host screen information utilizingthe client application.
 13. The computer program product of claim 12,wherein the client application comprises a web browser and wherein themonitoring application comprises an notification code.
 14. The computerprogram product of claim 13, wherein the notification code is providedwith updated legacy host screen information, the computer programproduct further comprising: computer readable program code means forextracting the notification code from the host screen information; andcomputer readable program code means for executing the notificationcode.
 15. The computer program product of claim 13, wherein the updatedlegacy host screen information comprises a Markup Language.
 16. Thecomputer program product of claim 12, wherein the updated legacy hostscreen information comprises terminal emulation information.
 17. Thecomputer program product of claim 12, wherein the first and secondconnections are conducted via a single communications link.
 18. Thecomputer program product of claim 12, wherein the server applicationprovides updated legacy host screen information to a second clientapplication in response to requests from the second client application,the computer program product further comprising: computer readableprogram code means for identifying the client application that requestedthe updated legacy host screen information.
 19. A computer programproduct of providing updated legacy host screen information to a clientapplication as terminal emulation between a legacy host system and theclient application, the client application utilizing a request-responsecommunications model, the computer program product comprising: acomputer-readable storage medium having computer-readable program codemeans embodied in said medium, said computer-readable program code meanscomprising: computer readable program code means for establishing afirst connection between the client application and a serverapplication, wherein the server application provides updated legacy hostscreen information to the client application in response to requestsfrom the client application using an HTTP request-responsecommunications model, wherein the updated legacy host screen informationis based on asynchronously generated information formatted for acharacter terminal display of a host legacy system as part of terminalemulation provided between the client application and the host legacysystem; computer readable program code means for establishing a secondconnection between a monitoring application and the server application;computer readable program code means for receiving updated legacy hostscreen information from a host system; computer readable program codemeans for transmitting a notification of the availability of updatedlegacy host screen information to the monitoring application over thesecond connection using the HTTP request-response communications modelresponsive to receiving the updated legacy host screen information;computer readable program code means for receiving a request for theupdated legacy host screen information from the client application overthe first connection using the HTTP request-response communicationsmodel; and computer readable program code means for transmitting thereceived updated legacy host screen information to the clientapplication over the first connection in response to receiving therequest for the updated legacy host screen information from the clientapplication.
 20. The computer program product of claim 19, wherein theclient application comprises a web browser and wherein the monitoringapplication comprises an notification code.
 21. The computer programproduct of claim 20, wherein the computer readable program code meansfor transmitting the received updated legacy host screen informationfurther comprises: computer readable program code means forincorporating the notification code in the updated legacy host screeninformation transmitted to the client application.
 22. The computerprogram product of claim 19, wherein the server application providesupdated legacy host screen information to a second client application inresponse to requests from the second client application, the computerprogram product comprising: computer readable program code means foridentifying the client application that requested the updated legacyhost screen information.
 23. A system for displaying updated legacy hostscreen information utilizing a web browser as part of terminal emulationprovided between the client application and the web browser, comprising:a host server application; a browser application configured tocommunicate with the host server application using an HTTPrequest-response communications model; a first connection configured toprovide communication between the host server application and thebrowser application using the HTTP request-response communicationsmodel; a notification application operably associated with the browserapplication that notifies the browser application to request updatedlegacy host screen information from the host server application fordisplay by the browser application using the HTTP request-responsecommunications model, wherein the updated legacy host screen informationis based on asynchronously generated information formatted for acharacter terminal display of a host legacy system as part of terminalemulation provided between the client application and the host legacysystem; and a second connection, established by the notificationapplication, configured to provide communication between the host serverapplication and the notification application using the HTTPrequest-response communications model.
 24. A system according to claim13, wherein the first and second connections comprise sockets.
 25. Asystem according to claim 23 wherein the notification application isembedded in a web page provided to the browser application by the hostserver application.